In a line of questioning about the investigation into Russia’s interference in the 2016 election and President Trump’s firing of FBI Director James Comey, Wyden and Sessions went back and forth, with Sessions insisting that his letter recommending Comey’s firing “did not violate my recusal” from the Russia probe.

“That answer, in my view, does not pass the smell test,” Wyden shot back. “The day before you wrote your letter, [Trump] tweeted that the collusion story was a hoax.”

Sessions recused himself from the Justice Department’s probe into whether Trump associates colluded with the Kremlin after it emerged that he had had undisclosed meetings with Russia’s ambassador.

Trump abruptly fired Comey last month, and the White House initially indicated that the action was based on the recommendations of Sessions and his deputy attorney general. But Trump quickly dismissed that explanation, saying he fired Comey for being a “showboat.” Comey said last week that he believed he was fired because of the FBI’s Russia probe.

On Tuesday, Wyden and Sessions exchanged fireworks about other topics as well.

Wyden opened his questioning by declaring, “Stonewalling of any kind is unacceptable.” The Oregon Democrat then asked Sessions if he knew of any concerns in the FBI or elsewhere in government about whether Sessions should step aside from the Russia investigation.

“Sen. Wyden, I am not stonewalling. I am following the historic policies of the Department of Justice,” Sessions said. “You don’t walk into any hearing or committee meeting and reveal confidential communications with the president of the United States.”

Sessions noted that he recused himself from the Russia probe shortly after taking office as attorney general. He added that he hadn’t accessed files about the probe, met the investigators or received documents about the investigation. He said that what he knew of the investigation was mostly based on public media coverage.

“Respectfully, you’re not answering the question,” Wyden said. “Mr. Comey said there are matters with respect to the recusal that were problematic and he couldn’t talk about them. What are they?”

Sessions fired back at Wyden, insisting, “There are none, Sen. Wyden. There are none. I can tell you that for absolute certainty. This is a secret innuendo being leaked out there about me, and I don’t appreciate it. I’ve tried to give my best and truthful answers to any committee I’ve appeared before.”